Governing mechanism for water-driven turbines.



A. GAGG.

GOVERNING MECHANISM FOR WATER DRIVEN TURBINES.

APPLICATION FILED JULY 14, 1915.

I Patehted Apr. 25,1916.

3 SHEETS-SHEET I.

A. GAGG.

GOVERNING MECHANISM FOR WATER DRIVEN TURBINES.

APPLICATION FILED JULY 14, 1915.

Patented Apr. 25, 1916.

3 SHEETS-SHEET 2.

A. GAGG. GOVERNING MECHANISM FOR WATER DRIVEN TURB INES.

APPLICATION FILED JULY 14. 1915.

Patented Apr. 25,1916.

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m nnnnn W an'rou ease, or airmen, sw rznnLaun, assre non 'ro THE FIRMAKTIENGESELL- SCHAFT DER MASCHINENFABRIKEN ESCHER, WYSS & 00., orZURICH, swrrzna- LAND.

Specification of Letters Patent.

GOVERNING MECHANISM FOR WAT1ER-DRIVEN TURBINES.

Patented Apr. 25, 19116..

Application filed July A, 1915. Serial No. 39,847.

To all whom it may concern:

Be it known that I, ANTON GAGG, a citizen of the Republic ofSwitzerland, residing. at Zurich, Switzerland, have invented new anduseful Improvements in or Relating to Governing Mechanism forater-Driven Turbines and other Prime Movers; and I do hereby declarevthefollowing to be a full, clear, and exact description of the invention,such as will enableothers skilled in the art to which it appertains tomake and use the same,reference being had to the accompanying drawings,and to letters or figures of reference marked thereon, which form a partof this specification.

This invention relates to means for securing freedom from oscillation ingoverning mechanism for prime movers and more particularly water-driventurbines by the use of hydraulic, indirectly-acting speed governors.

The essential features of the present invention consist in providingmeans whereby the travel of the controlling organ of the auxiliary motorparticipates only within relatively narrow limits of the movements ofthe centrifugal governor. A yielding member, for instance a dash-pot, isso connected with a controlling linkage that the centrifugal governor iscapable of continuing its travel after the controlling organ has reachedits end positions. The centrifugal governor, immediately upon areversing of its movement, imparts to the controlling organ the samedegree of movement.

A constructional embodiment of the invention consists in providing, inconnection with the dash pot, springs that act to return the dash potcylinder after each displace-- ment to its mid position, for the purposeof restoring after each governing the position of the controlling organin dependence upon the centrifugal governor, said position beingrequired for keeping a certain speed or number of revolutions of theprime mover.

The apparatus is adapted for use both in connection with constant speedgoverning systems and systems of the kind wherein a certain given newspeed or number of revolutions corresponds to each new load.

The accompanying drawings illustrate constructional examples ofmechanism embodying the invention adapted for use in connection withwater-driven turbines, and also illustrate diagrammatically thegoverning o erations or effects obtainable by means 0 the governingmechanism according to the present invention.

F gure 1 is a front elevation, partly in sectlon of one form ofconstruction. Fig. 2 1s a vertical section of the casing of thecontrolllng valve, showing the governing piston arranged within thecasing in its lowest position. Fig. 3 is a vertical section of thecasing of the dash-pot, showing the piston of the latterdisplacedrelatively to the middle of the dash pot casing. Fig. 4 is a verticalsectioncorresponding to Fig. 2 showing the governlng piston in itsuppermost position. Fig. 5 illustrates diagrammatically the governingoperations or effects obtainable by means of the mechanism shown inFigs. 1 to 4. Fig. 6 is a vertical section of a second constructionalform. Fig. 7 is a vertical central section of the dash potshown' in Fig.6, illustrating the parts in another position. Fig. 8 illustratesdiagrammatically the governing operations or effects obtain able bymeans of the mechanism shown in Figs. 6 and 7. Fig. 9 is a verticalsection of a third constructional form. Fig. 10 illustratesdiagrammatically, the governing operations or effects obtainable withpositive and negative returning arrangements respectively. Fig. 11 is avertical section of a dash-pot, illustrating springs arranged externallyto the dash-pot cylinder. Fig. 12 is a vertical section of a frictioncoupling that may be used instead of a dash pot. Fig. 13 is a horizontalsection at line A-B of Fig. 12. V

In the example shown in Fig. 1 the casing 2 of the controlling valve forthe auxiliary motor which can work with a fluid under pression forinstance water or oil under pressure has stops, by which the travel ofthe governing piston 3 movable within the casing 2 is kept withinnarrow. limits. In the present case the auxiliary motor comprises thecasing 4 and differential pistons 5. 5 and is connected to a pipe system30. that receives water under pressure from the main supply pipe .81leading to the water turbine 32, that drives also the centrifugalgovernor 1. A. dash pot is intercalated in the linkage system betweenthe governing piston 3 and the centrifugal governor 1. The dash potconsists essentially of a cylinder 6 and a piston 7. The spaces in thedash pot cylinder 6 above and below such piston are tilled with oil andthe dash piston is formed with a small perforation 11 that places thesaid spaces in communication with each other. l pon the centrifugalgovernor 1 being caused to rotate at'a higher speed owing to the load onthe prime mover being l ghtened its sleeve raises the left hand end ofthe. lever 8 and turns such lever in a clockwise direction about itsstationary fulcrum 9. The right hand end of the lever 8, acting throughthe link 10 thereupon pressesthe dash pot piston 7 downward. Theperforation 11 is however so small in diameter; that in the short periodof the movement, which is momentarily in a downward direction itis notpossible for a suflicient quantity of oil to flow from the lower to theupper side of the piston 7 to admit of the'piston moving freelyrelatively to the cylinder 6. A momentary driving connection, althoughofa slightly elastic or yielding nature. is accordingly set up be tweenthe piston 7 and'the cylinder 6, and consequently the piston 3 of thecontrolling valve to which the cylinder is rigidly connected, willalsobe pressed downward into the position shown in Fig. 2. In this positionof the controlling piston 3 the way is clear to the outlet pipe 12 forthe Water under pressure on the right hand side of the large piston 5 ofthe auxiliary motor, so that the pressure on the right hand side of thepiston 5 falls. The continuously prevailing high pressure of the waterbetween the large piston 5 and the small piston 5 is consequently ableto push the two pistons to the right and thus by means of the link 14and lever 15 to turnthe main governor shaft. 16 in a counter-clockwisedirection, this resulting in a closing movement of the main admissionvalve 33 or equivalent devices of the prime mover. A slight upwardmovement of the sleeve of the centrifugal governor 1 will suffice topush the piston 3 of the controlling valve far enough downward to causesuch piston to travel the entire length of its stroke, as such travel isquite small relatively to the whole travel of the governor sleeve. Itneed for instance only amount to one millimeter out of the mid-position.The right hand end of the lever 8 is however capable of travelingaltogetherthrough a distance that is much greater than the aforesaidtravel of the piston 3. Even when the controlling piston 3 is seated atthe bottom in the casing 2, see Fig. 2, the speed governor isstillcapable of further movement in theoriginal direction, as the dash potpiston I b 7 then becomes displaced downward to a corresponding extentwithin the dash pot cylinder 6 and displaces the oil below it up throughthe perforation 11, the said piston moving into the position shown inFig. 3. When however the speed of the centrifugal governor decreasesafter the main inlet valves or equivalent devices have been moved intothe position corresponding to the new load, so; that the governor sleevebegins to descend, the dash pot piston 7 which at this time is beingdrawn upward by the right hand end of the lever 8 again becomesmomentarily coupled, by means of the oil over such piston, to the dashpot cylinder 6, the piston at this time being in the position shown inFig. 3, it having been moved downward out of its mid position. Thepiston 7 'as it is being drawn upward draws upward along with it thedash pot cylinder 6 and consequently the piston 3 of the controllingvalve, until the latter piston reaches its mid position, a fresh periodof repose being thereby set up. This governing operation is graphicallyrepresented in Fig. 5 wherein the time corresponding to any givengoverning operationis indicated as abscissae measured from left toright, the ordinates representing on the one hand the speed or number ofrevolutions n of the prime mover (the thin line) and on the other handthe amount of opening 0 of the main inletvalves or the like (the heavyline). At the point of time t suppose the preexisting state or repose tobe interrupted by a lightening of the load on the waterdriven turbine.As a result the turbine speed will be accelerated and the centrifugalgovernor l raises its sleeves and acts as hereinbeforedescribed, throughthe dash pot 6-7, distributing valve 2-3, and auxiliary motor 455, toturn the governing shaft 16 in a counter clockwise direction and thusclose the main distributing valves or the like.

Referring to the diagram, Fig. 5, the speed of the prime mover isrepresented as having had the value n during the first state or periodof repose, that is to say, up to the time t and the main inlet valves orthe like were open by an amount 0 Up to the time F, the speed of theprime mover rises to the amount n while at the same time the centrifugalgovernor acts in accordance with the governing operation hereinbeforedescribed to bring about a reduction of the sectional area of opening ofthe admissionvalves or the like down to the amount 0 At the same 23 theamount of energy transmitted by the water on the turbine shaft isexactly equal to the duty required of the turbine at the increased speeda". The auxiliary motor 4, 5, 5 however moves further in a direction toclose the main admission valves thereby causing the speed of rotation tofall from the value 71?. This in turn causes the governor sleeve todescend and thus raise the dash pot piston 7. As already stated the dashpot piston 7 draws the dash pot cylinder 6 and consequently the piston 3of thecontrolling valve upward, that is to say, draws the piston 3 intoits mid posii of the cylinder 17 is greater.

niece tion; The closing movement of the main admission valves or thelike is momentarily interrupted. Now it is to be understood that thetravel of the controlling valve is intended to be very small as comparedwith that of the rod 10 or the sleeve of the centrifugal governor v1,for instance only as 1 to 20. llnthis case a fall in the speed ofrotation of 1/20th of the amount of the degree of nonuniformity of thespring governor (amounting say,to a that is to say, a fall of only about1/ 5th of the speed 71 will sullice to bring about the return of thecontrolling piston 3 to its mid position as hereinbefore described.

As indicated in Fig.- 5 the speed falls from the value a only by thevery small amount between that point and n where a fresh state of reposeisset up and at which point the main admission valves or the like areopen by the amount U Now if the device constituting the invention hadnot been employed the speed would have fallen to the value a and beyond.The closing movement of the admission valves would have continued for acorrespondingly long period, that is to say, up to the time t, at whichpoint the amount of admission of the prime mover would have alreadybecome far too small, with the result that a permanent oscillation orhunting action would be set up in a well-known manner, as indicated bythe dot and dash lines in Fig. 5.

.ln the fresh state of repose before referred to'at the point t the dashpot piston 7 occupies relatively to its cylinder 6 the position shown inFig. 3 in which it is displaced in a downward direction and which isaccordingly not identical with the mid position shown in Fig. 1. speed awill in general be by such an amount higher than the original speed n aswould not be admissible for instance for driving electric generatingmachines. lt is however possible to restore the original speed 11. forthe new state of repose if the dash pot be constructed as shown in Fig.6 and substituted for the simple dash pot shown in Fig. 1. ln thisconstruction it is only in its middle portion that the bore or internaldiameter of the dash pot cylinder 17 is made sulliciently small tocorrespond exactly to the dash pot piston 18. Above and below thisportion the internal diameter Bearing against the shoulders thus formedare freely fitting rings 19 and 20 loaded by springs 21 and 22. Now uponthe piston 18 being forced downward out of its mid position by thecentrifugal governor owing to a reduction in the load on the waterdriven turbine,

it will force the ring 20 downward and ac-' cordinrgly compress thelower spring 22, see Fig. 7. The upper spring 21 remains in its previousposition as its supporting ring Moreover the new 19 rests against theshoulder formed by the constructed part of the casing 17. Owing to theone-sided or unbalanced action of the spring 22 the piston 18 is nolonger in equilibrium relatively to the cylinder 17 and the spring 22tends to force the piston back relatively to the cylinder 17 into themutual mid position shown in Fig. 6. A mutual action will now take placein governing mecha' nism fitted with a dash pot constructed in thismanner, betweenthe centrifugal govbeen caused to run at its originalspeed. In

this way the turbine will be "seen to have been provided with means forgoverning at constant speed. The action of the arrangement isillustrated graphically in Fig. 8. Up to the time t the initial state ofrespose or dwell has lasted with a certain load. The speed during thisperiod amounted'to n and the main admission valves or the like of theturbine were opened by the amount 0 After the reduction in "load thespeed of the turbine rises to-the amount a and then falls to the amountat. Up to this point the action is identical with that already describedwith reference to Fig. 5 up to the time 25 Now however the action of thecompressed spring 22 comes into play. The

dash pot cylinder 17 and along with it the controlling piston 3 arepushed downward slightly by the action of this spring and only slowly orjust at such a speed'as allowed by the small perforation in the dash potpiston 18, thus allowing the auxiliary motor to con tinue its closingmovement. As a result the speed falls from the amount a (Fig. 8),

which corresponds to the amount of in Fig. 5, still further and thecontrolling piston 3 is returned to its mid position owing to thefalling of the governor sleeve caused thereby. Let this state of thingsbe supposed to have been attained at the time F. The main admissionvalves are then open by the amount 0 which is somewhat less than the l lamount corresponding to the new load at the normal speed. The speed hasmomentarily the value 12, and owing to the slightly too small amount ofopening of the main ad mission valves is constantly falling. This wouldat once again bring about an opening movement were it not for the factthat the dash pot cylinder 17 together with the controlling piston 3 isfurther displaced relatively to the dash pot piston 18 in the direc- 1tion of closing under the action of the spring 22. By properlyproportioning the size of the perforation in the dash pot piston 18 itis possible to insure that the upward movement'of the piston 18 causedby the falling of the sleeve of the spring governor and the downwardmovement of the dash pot cylinder relatively to the dash piston willneutralize each other, so that the controlling piston 3 will remain inits mid position until the ring 20 again bears on the shoulder formed bythe portion of the dash pot cylinder 18 of reduced diameter and the onesided action of the spring 22 ceases to exist. At this moment thecontinued falling of the speed causes the main admission valves of thewater driven turbine to be again opened, to an extent 0 correspondingtothe new load, with the result that at the time t the new state ofrepose or dwell is attained. As in this new state of repose the dash potpiston 18 again occupies the same position relatively to the dash potcylinder 17 as at the-time t before the beginning of the governingoperation, the position of the governor sleeve will also be the same,and the speed a after the close of the governing operation will be equalto the speed 17, before the latter.

Fig. 9 shows how it is possible, ascompared with the simpler governingmechanism illustrated in Fig. l, to arrange between the auxiliary motor,or in effect the main governing shaft 16, and the lever 8 of thecentrifugal governor, instead of the dash po't 6, 7 shown in Fig. 1,not. only the dash pot shown in Figs. 6 and 7 fitted with returningsprings, but in addition thereto which in itself is known. Th

areturning linkage system of a' construction is arrangement has for itsobject to establish a certain relation "of dependence, necessary forcertain power-supply services, between the load on one hand and thespeed on the other. For the sake of simplicity in Fig. 9 all parts thatare similar in the arrangements shown in Fig. 1 and Fig. 6 respectivelyare denoted by the same numbers as already used in those figures. In thearrangement shown in Fig. 9 the pivotal axis 9 of the governor lever 8is no longer stationary or fixed, as

in Fig. 1, but is carriedon the returning ing displacement or dwell ofthe point .9

during a governing operation has the effect of com elling the sleeve ofthe spring governor to assume a different POSitlOII .in order to set upa new state of repose, with the result that a lasting alteration on thespeed obtains in the case of the new load. Now the difference in thespeed between of the spring governor 1 must occupy a higher positionafter the close of a governing operation with the result that a higherspeed will correspond to the new lighter .-load (positive returning). Ifthe link 27 be arranged in the dotted line position 27, the point 9 willbe lowered at every closing novemeht of the shaft 16, thus causing thesleeve of the spring governor to occupy a lower position after thegoverning operation. The speed will then be less than before for thenew, lighter load (negative returning). In all these cases a method ofgoverning practically free from oscillation or hunting is also obtainedby means of apparatus forming the subject matter of the lnvention. Agoverning operation in general takes place in a perfectly similar mannerto what has been hereinbefore described in reference to constant speedgoverning without returning mechanism, Fig. 8. The only differenceconsists .in the fact that a greater or lesser displacement of the dashpot piston 18 in the dash pot cylinder 17 takes place during a governingoperation, other conditions being equal. The amount of displacement willbe less when the movement imparted to the rod 10 by the returningmechanism is in the opposite direction to that caused by the centrifugalgovernor, as is the case in positive returning. The amount of thedisplacement will be greater when the movements of the returningmechanism and the centrifugal governor .act in the same direction on therod 10.

The course of a governing operation with positive and negative returningarrangements respectively is illustrated diagrammatically in Fig. 10,the full line curves applying to positive and the dash-and-dot curves tonegative returning arrangements. In the case of the positive returningarrangement the speed a attained at the time at the close of thegoverning operation is higher by a certain amount than the speed nbefore the lightening of the load. Conversely. in the negative returningar-' rangement the speed a during the subsequent period of dwell andwhich is attained at the time t is less by a certain amount than thatobtaining before the reduction in load.

In all the cases hereinbefore described it is essential toward attainingfreedom from oscillation or hunting in governing mechanism that thecontrolling piston 3 shall be nieaaea returned to its mid position bythe dash pct 17 .to 22 immediately after the change in the speed hasbeen set up, and that this shall necessitate only a very small backwardmovement or reverse change in the speed and only a very brief period oftime, by which means it state of equilibrium (which always prevails atthe time when the change in the speed takes place) between the amount-ofenergy supplied to the prime mover and the amount of power furnished bythe latter, to be maintained at least approximately constant until theclose of the governing opertions.

The returning spring 21 shown in Fig. 6 comes into action when the loadon the turbine is increased, the spring 22 then remaining inoperative.The dash pot cylinder may in some cases be filled with water, air or thelike, instead of oil. As an alternative, th springs may be arrangedexternally to thedash pot cylinder and act on the piston rod instead ofon the piston itself as has been shown in Fig. 11. The springs 3.4 restwith their one end on the outside of the dash pot cylinder while theupper end of the upper spring is fixed to the rod of the controllinglinkage system that is connected to the dash pot piston and the lowerend of the lower spring is fixed to the rod of the controlling linkagesystem that is connected to the controlling valve for the auxiliarymotor. The working of this dash pot is the same as the working describedwith reference to Fig. 6.

If desired some other device equivalent in action to a dash pot forinstance a friction coupling, may be employed instead of a dash potsucha friction coupling has been shown in Figs. 12 and 13. The rod 35 ofthe controlling linkage system, intercalated between the centrifugalgovernor and controlling valve, that is connected to the controllingvalve carries at its upper end a piston 36 guided by two guide shoes 37and 38 within a cylindercasing 39. The two guide shoes are arrangedopposite to each other in the same diameter and are pressed by means ofsprings 40 and 41 toward the piston 36. The casing 39 is hanged up tothe rod 42 of the controlling linkage system. The working of such afriction coupling is the same as the Working of a dash pot. Upon thecentrifugal governor being caused to rotate at a higher speed owing tothe load on the prime mover being lightened, the rod 42 presses thecylinder casing 39 downward.

The friction of the guide shoes 37 and 38 is so great, that in the shortperiod of the movement, which is momentarily in a downward direction, itis not possible to overcome this friction and to admit of the pistonmoving relatively to the two guide is rendered possible for theshoes. Amomentary driving connection is accordingly set up between the piston 36and the controlling valve and consequently the piston 6 of thecontrolling valve will also be pressed downward till its sitting uponthe lower stop of the valve casing. From this moment by a furtherdownward movement of the the guide shoes will be overcome, this beingpossible by the yielding nature of the friction coupling. By anoccurrent upward movement, the friction coupling will act as a rigidconnection till the piston 6 has reached the upper stop of the casing.

Claims: v

1. In a governing mechanism for prime movers the combination of a maingovernor shaft, an auxiliary motor acting upon said shaft, a controllingorgan for said auxiliary motor traveling only within relatively narrod42, the friction of row limits, a centrifugal, governor, a con trollinglinkage system connecting said governor with said controlling organ, ayielding member in connection with said linkage sys tem capable ofcontinuing its travel after the controlling organ has reached its endpositions, said yielding member being capa ble of imparting to thecontrolling organ, upon a reversing movement of the governor, the samedegree of movement, substantially as described and for the purpose setforth.

2. In a governing mechanism for Waterdriven turbines the combination ofa main governor shaft, a hydraulic auxiliary motor acting upon saidshaft, a controlling valve for said auxiliary motor traveling withinrelatively narrow limits, a centrifugal governor, a controlling linkagesystem connecting the centrifugal governor with the controlling valve, ayielding member in connection with said linkage system capable ofcontinuing its travel after the controlling valve has reached its endpositions, said yielding member being capable ofimparting to thecontrolling organ, upon a reversing movement of the governor, the samedegree of movement, substantially as described and for the purpose setforth. I

3. In a governing mechanism for prime movers the combination of a maingovernor shaft, an auxiliary motor acting upon said shaft, a controllingorgan for said auxiliary motor traveling only within relatively narrowlimits, a centrifugal governor, a controlling linkage system connectingsaid governor with said controlling organ, a dash pot in connection withthe controlling linkage system and consisting of a cylinder and aperforated piston therein, substangiallly as described and for thepurpose set ort 4. In a governing mechanism for waterdriven turbines thecombination of a main governor shaft, a hydraulic auxiliary motor saidcasing,

mg member acting upon said shaft, a controlling valve for saidauxiliarymotor traveling Within relatively narrow limits, a centrifugal governor,a controlling linkage system connecting the centrifugal governor Withthecontrolling valve, a dash pot in connection with the controlling linkagesystem and consisting of a cylinder'and a perforated piston therein,substantially as described and for the purpose set forth.

In a governing mechanism for' Waterdriven turbines the combination of amain governor shaft, a hydraulic auxiliary motor comprising a casing anddifferential pistons acting upon said shaft 1 and a pipe system forfluid under pression in connection with a controlling valve with stopsintercalated in said pipe system, a centrifugal governor, a controllinglinkage system connecting the centrifugal governor With the controllingvalve, a dash pot intercalated in the controlling linkage system andconsisting of a cylinder and a perforated piston therein, substantiallyas described and for the purpose set forth.

In a. governing mechanism for prime movers the combination of a maingovernor shaft, an auxiliary motor acting upon said shaft, a controllingorgan for said auxiliary motor traveling only within relatively narrowlimits, a centrifugal governor, a controlling linkage system connectingsaid governor with said controlling organ, a yieldin connection withsaid linkage system capable of continuing its travel after i thecontrolling organ has reached its end positions, said yielding memberbeing capable of imparting to the controlling organ, upon a reversingnor, the same degree of movement, springs movement of the goverprovidedin connection with said yielding member acting to return it in its midpositionafter each displacement for restoring after each governing thegiven position of the controlllng organ in dependence upon thecentrifugal governor, substantially as described and for the purpose setforth.

I controlling valve in 7. In a governing mechanism for waterdriventurbines the combination of a main. governor shaft, a hydraulicauxiliary motor acting upon said shaft, a controlling valve for saidauxiliary motor traveling within relatively narrow limits, a centrifugalgovernor, a controlling linkage system connecting the centrifugalgovernor with the controlling valve, a dash pot jntercalated in thecontrolling linkage'system and consistmg of a cylinder and a perforatedpiston therem, springs provided in connection with the dash pot andacting to return the dash pot cylinder after each displacement to itsmid position for restoring after each governing the given position ofthe controlling valve in dependence upon the centrifugal governor,substantially as described and for the purpose set forth.

8 In a governing mechanism for waterdriven turbines the combination of amain governor shaft, a hydraulic auxiliary motor comprising a casing anddifferential pistons acting upon said shaft and a pipe system for fluidunder pression in connection with saidcasing, a controlling valve withstops intercalated in said pipe system, a centrifugal governor, acontrolling linkage system connecting the centrifugal governor with thecontrolling valve, a dash pot intercalated in the controlling linkagesystem and consisting of a cylinder and a perforated pistontherein,springs provided in connection with the dash pot and acting to returnthe dash pot cylinder after each displace.- ment to its mid position forrestoring after each governing the given position of the dependence uponthe centrifugal governor, substantially as described and for the purposeset forth.

In testimony that I claim the foregoing as my invention, I have signedmy name in presence of two subscribing witnesses.

ANTON GAGG.

Witnesses ERNST FISCHER, CARL GUBLER.

